Circuits that provide level shifting from one signal mode to another signal mode are known. Circuits that provide an active pull-up function or an active pull-down function on an input signal are also known. An example of the latter type of circuit is the Linear TechnologyLTC1694, which provides active pull-up using a multiple discreet components.
Providing these functions together, however, has not been needed, and such is particularly true with respect to applications where these functions operate on the same signal on the same bus. It has been found, however, that providing these functions together on a single bus has advantages, and that there are even further advantages to providing such functions on a single integrated circuit chip that is designed and fabricated using conventional techniques.